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a-EQ: Tidy transfer function calculation

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This commit is contained in:
Damien Zammit 2016-07-14 02:03:08 +10:00
parent 0b3d09b011
commit 0fdbbac99d
1 changed files with 102 additions and 49 deletions
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149
libs/plugins/a-eq.lv2/a-eq.c
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@ -447,93 +447,146 @@ run(LV2_Handle instance, uint32_t n_samples)
#endif
}
#ifdef LV2_EXTENDED
static float
eq_curve (Aeq* self, float f) {
float SR = self->srate;
double complex H = 1.0;
double theta = f * 2. * M_PI / SR;
double complex z = cexp(I * theta);
double complex zz = cexp(2 * I * theta);
static double
calc_peq(Aeq* self, int i, double omega) {
double complex H = 0.0;
double complex z = cexp(I * omega);
double complex zz = cexp(2. * I * omega);
double complex zm = z - 1.0;
double complex zp = z + 1.0;
double complex zzm = zz - 1.0;
double A;
double m0, m1, m2, g, k;
double A = pow(10.0, self->v_g[i]/40.0);
double g = self->v_filter[i].g;
double k = self->v_filter[i].k;
double m1 = k * (A * A - 1.0) / A;
H = (g*k*zzm + A*(g*zp*(m1*zm) + (zm*zm + g*g*zp*zp))) / (g*k*zzm + A*(zm*zm + g*g*zp*zp));
return cabs(H);
}
static double
calc_lowpass(Aeq* self, double omega) {
double complex H = 0.0;
double complex z = cexp(I * omega);
double complex zz = cexp(2. * I * omega);
double complex zm = z - 1.0;
double complex zp = z + 1.0;
double complex zzm = zz - 1.0;
double g = self->v_filter[5].g;
double k = self->v_filter[5].k;
H = (g*g*zp*zp) / (zm*zm + g*g*zp*zp + g*k*zzm);
return cabs(H);
}
static double
calc_highpass(Aeq* self, double omega) {
double complex H = 0.0;
double complex z = cexp(I * omega);
double complex zz = cexp(2. * I * omega);
double complex zm = z - 1.0;
double complex zp = z + 1.0;
double complex zzm = zz - 1.0;
double g = self->v_filter[0].g;
double k = self->v_filter[0].k;
H = zm*zm / (zm*zm + g*g*zp*zp + g*k*zzm);
return cabs(H);
}
static double
calc_lowshelf(Aeq* self, double omega) {
double complex H = 0.0;
double complex z = cexp(I * omega);
double complex zz = cexp(2. * I * omega);
double complex zm = z - 1.0;
double complex zp = z + 1.0;
double complex zzm = zz - 1.0;
double A = pow(10.0, self->v_g[0]/40.0);
double g = self->v_filter[0].g;
double k = self->v_filter[0].k;
double m0 = self->v_filter[0].m[0];
double m1 = self->v_filter[0].m[1];
double m2 = self->v_filter[0].m[2];
H = (A*m0*zm*zm + g*g*(m0+m2)*zp*zp + sqrt(A)*g*(k*m0+m1) * zzm) / (A*zm*zm + g*g*zp*zp + sqrt(A)*g*k*zzm);
return cabs(H);
}
static double
calc_highshelf(Aeq* self, double omega) {
double complex H = 0.0;
double complex z = cexp(I * omega);
double complex zz = cexp(2. * I * omega);
double complex zm = z - 1.0;
double complex zp = z + 1.0;
double complex zzm = zz - 1.0;
double A = pow(10.0, self->v_g[5]/40.0);
double g = self->v_filter[5].g;
double k = self->v_filter[5].k;
double m0 = self->v_filter[5].m[0];
double m1 = self->v_filter[5].m[1];
double m2 = self->v_filter[5].m[2];
H = ( sqrt(A) * g * zp * (m1 * zm + sqrt(A)*g*m2*zp) + m0 * ( zm*zm + A*g*g*zp*zp + sqrt(A)*g*k*zzm)) / (zm*zm + A*g*g*zp*zp + sqrt(A)*g*k*zzm);
return cabs(H);
}
#ifdef LV2_EXTENDED
static float
eq_curve (Aeq* self, float f) {
double complex response = 1.0;
double SR = (double)self->srate;
double omega = f * 2. * M_PI / SR;
// low
if (self->v_filtog[0]) {
A = pow(10.0, self->v_g[0]/40.0);
m0 = self->v_filter[0].m[0];
m1 = self->v_filter[0].m[1];
m2 = self->v_filter[0].m[2];
g = self->v_filter[0].g;
k = self->v_filter[0].k;
if (self->v_shelftogl) {
// lowshelf
H *= (A*m0*zm*zm + g*g*(m0+m2)*zp*zp + sqrt(A)*g*(k*m0+m1) * zzm) / (A*zm*zm + g*g*zp*zp + sqrt(A)*g*k*zzm);
response *= calc_lowshelf(self, omega);
} else {
// hp:
H *= zm*zm / (zm*zm + g*g*zp*zp + g*k*zzm);
response *= calc_highpass(self, omega);
}
}
// peq1:
if (self->v_filtog[1]) {
A = pow(10.0, self->v_g[1]/40.0);
m1 = self->v_filter[1].m[1] / A;
g = self->v_filter[1].g;
k = self->v_filter[1].k;
H *= (g*k*zzm + A*(g*zp*(m1*zm + g*m2*zp) + (zm*zm + g*g*zp*zp))) / (g*k*zzm + A*(zm*zm + g*g*zp*zp));
response *= calc_peq(self, 1, omega);
}
// peq2:
if (self->v_filtog[2]) {
A = pow(10.0, self->v_g[2]/40.0);
m1 = self->v_filter[2].m[1] / A;
g = self->v_filter[2].g;
k = self->v_filter[2].k;
H *= (g*k*zzm + A*(g*zp*(m1*zm + g*m2*zp) + (zm*zm + g*g*zp*zp))) / (g*k*zzm + A*(zm*zm + g*g*zp*zp));
response *= calc_peq(self, 2, omega);
}
// peq3:
if (self->v_filtog[3]) {
A = pow(10.0, self->v_g[3]/40.0);
m1 = self->v_filter[3].m[1] / A;
g = self->v_filter[3].g;
k = self->v_filter[3].k;
H *= (g*k*zzm + A*(g*zp*(m1*zm + g*m2*zp) + (zm*zm + g*g*zp*zp))) / (g*k*zzm + A*(zm*zm + g*g*zp*zp));
response *= calc_peq(self, 3, omega);
}
// peq4:
if (self->v_filtog[4]) {
A = pow(10.0, self->v_g[4]/40.0);
m1 = self->v_filter[4].m[1] / A;
g = self->v_filter[4].g;
k = self->v_filter[4].k;
H *= (g*k*zzm + A*(g*zp*(m1*zm + g*m2*zp) + (zm*zm + g*g*zp*zp))) / (g*k*zzm + A*(zm*zm + g*g*zp*zp));
response *= calc_peq(self, 4, omega);
}
// high
if (self->v_filtog[5]) {
A = pow(10.0, self->v_g[5]/40.0);
m0 = self->v_filter[5].m[0];
m1 = self->v_filter[5].m[1];
m2 = self->v_filter[5].m[2];
g = self->v_filter[5].g;
k = self->v_filter[5].k;
if (self->v_shelftogh) {
// highshelf:
H *= ( sqrt(A) * g * zp * (m1 * zm + sqrt(A)*g*m2*zp) + m0 * ( zm*zm + A*g*g*zp*zp + sqrt(A)*g*k*zzm)) / (zm*zm + A*g*g*zp*zp + sqrt(A)*g*k*zzm);
response *= calc_highshelf(self, omega);
} else {
// lp:
H *= (g*g*zp*zp) / (zm*zm + g*g*zp*zp + g*k*zzm);
response *= calc_lowpass(self, omega);
}
}
return cabs(H);
return response;
}
static LV2_Inline_Display_Image_Surface *